move subscribe into action menu

Attached:

in backlog: https://bugzilla.wikimedia.org/show_bug.cgi?id=69795

So to clarify this is an enhancement request that reads as follows:

Given I'm looking at a hidden topic
Then I do not see a watchlist star

Given I'm looking at a hidden topic
When I click the action menu (currently a 3 dot icon)
Then I see a subscribe link in the menu

To do this we will need to think about the behaviour when you click it?

I assume it is as follows but it would be good to have a design for it:

Given I'm looking at a hidden topic
And I click the action menu (currently a 3 dot icon)
When I click the subscribe link in the menu
then the topic is added to my watchlist
and the subscribe link text is now changing to unsubscribe?
and I get a notification?